How many o2 sensors are on a 99 mercury cougar v6 and where are they located
I just got done replacing the O2 sensors in my 99 Cougar due to throwing a P0135 malfunction code. There's 3. Facing the engine there's one in the front coming off of the front header, which is easy to get to. Another more tricky one if between the engine and the fire wall on the rear header pipe. The third is under the vehicle behind the transmission pan on top of the exhaust. In order to replace the O2 sensor near the fire wall you will need to remove the 4 retaining bolts for the ECM module and move it out of the way. Additionally you will need to remove the 2 retaining nuts for a wiring harness that is seated below the ECM module. Pay close attention to the connectors because the front and under vehicle O2 sensors have round connectors the one near the firewall has a squared connector. I was able to replace all 3 by myself in approximately 35 minutes. If your throwing a O2 heater malfunction code it is most likely going to be the sensor near the firewall. make sure that you know someone with a code reader so the code can be cleared. If you're do for an emmissions inspection be sure to put at least 40 miles on the new O2 sensor with different types of driving (e.g. highway, coasting, decellerated turns and rapid acceleration). Gotta love project cars for your kids!!
Should be 4. One in front of the catalytic converter and one after on both front and rear exhaust.
Hello,
There are four O2 sensors on your 99 mercury cougar. Two upstream (intake) and two downstream (exhaust). If you are standing in front of the vehicle find the exhaust manifold (close to the radiator and as low). The exhaust manifold is attached to the side of the head under the intake. On the exhaust manifold there will be round tubes with wires coming out of the top of them, these are the O2 sensors. The front two and the rear lower can be changed from under the vehicle (please use jack stands) and the rear upper is easily reached by the top of the vehicle by removing the coil pack bolts and pushing it aside (bit of a pain). Remember, if you take the wires off remember where they came from (has to be the same).
I hope this helps.
Thanks for the clarification. Did you replace them and then find you had to replace the cats as well?
No, I have not replaced the Catalytic Converters as I changed the O2 sensors before they went bad (about every 100.000K - but depends on vehicle). If you have excess fuel the cats burn this fuel but if you have too much excess fuel this can cause CAT failure (e.g. - they start glowing and continue to glow after the vehicle is shut off). Then, if your CAT's fail your muffelers(sp) usually fail as well because the fuel is not being burned in the CAT's the fuel burns in the muffeler causing failure.
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how much will be cost to change all this sensor ?
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